Wet or Dry Diamond Polishing Pads Our 4inch/100mm Velcro backed pads are diamond impregnated to the highest quality, which guarantees their consistent long life. Please don't confuse them with inferior diamond coated discs which are commonly found for sale at very cheap prices, ours are the best quality discs available on the market. Our diamond pads are intended to be used for finishing and lapping marble, granite, concrete and masonry, and can be used wet or dry. Using them wet sustains their useful life much longer.